Devices for aligning an adjustable sight element in sight systems are well known and have been in use for a number of years. For example, a U.S. Pat. No. 4,554,745 of Repa discloses an adjustable sight element for a rifle that comprises an aperture disc for a peep sight and an adjustable sight structure for a telescopic sight. The adjustable sight element is adjustably mounted for movement about a vertical axis and a horizontal axis in a stationary housing attached to a rifle. The magnitude or degree of the vertical and horizontal displacement of the adjustable sight element is indicated by a capacitance or optronic measuring device and is displayed digitally in electronic digital fields. The electronic component is located in a casing which is removably attached to the housing.
A more recent patent of DeBatty et al., U.S. Pat. No. 5,222,302 discloses a firearm sight aligner for mounting in the bore of a firearm includes a collimator arrangement having a defuser, a sighting grid, and an objective lens. The sighting grid is mounted in the collimator arrangement so that its position can be adjusted in azimuth and elevation in response to movement of exterior mounted adjusting screw mechanisms. The adjusting screw mechanisms each include a multi-start threaded screw in order to enable full translation of the grid over its full range of azimuth and elevation in one 360° revolution of each of the adjusting screw mechanisms.
A further approach to a gun sight zero checking device is disclosed in a U.S. patent of Johnson, U.S. Pat. No. 6,584,720. As recognized by Johnson, rifle righting devices, particularly telescopic sights are susceptible to movement on account of being dropped or bumped. At times, the sight mounting may loosen and the kick from the rifle may cause the sight to move. Such movement and/or damage may not be readily apparent. In addition the zero of a rifle also varies between individual users. Consequently, if someone other than the owner uses the gun the zero of the rifle may have been changed.
It is clear that there is still a demand for a device to permit the zero of a firearm to be quickly checked without firing the rifle. The Johnson patent discloses one such device. As disclosed a blank cartridge form is attached to a second scope by a bracket. To use the rifle is first sighted in then the blank cartridge form is inserted into the rifle chamber and the device is rotated around the chamber until a stop device protruding from the bracket touches the rifle's scope. The rifle is then placed in a firm rest with the crosshairs of the rifle scope centered on a target at a known distance and the second scope then adjusted to indicate the same aiming point. If the owner is later unsure whether the scope has lost zero, a target can be set up at the same distance, the device again mounted to the rifle, and the two scopes viewed to determine whether the same impact point is indicated. If it is not, the rifle scope can then be adjusted to the spot indicated by the device scope.
Notwithstanding the above, it is presently believed that there is a need and a potential commercial market for a device and a method for aligning an adjustable sight for a firearm in accordance with the present invention. There should be a demand and a commercial market for such devices because such devices are believed to be of higher accuracy than the prior art devices, durable, and capable of being manufactured at a competitive price. Further, the devices in accordance with the present invention allow for the rapid zeroing of a firearm without firing the weapon.